| 摘要 |
PURPOSE:To remove the overhangs of a nonphotosensitive polyimide produced at he time of the formation of via holes in the polyimide by the use of wet etching. CONSTITUTION:Concerning to an method of forming via holes in a multilayer interconnection, a nonphotosensitive polyimide precursor 13 is applied to a board 11, and the solvent is dried. And a via pattern 16 is formed by developing positive photoresist 14. Next, a process of wet-etching the nonphotosensitive polyimide 13 using an alkaline aqueous solution and forming via holes 17 is performed, and the positive photoresist 14 as exfoliated from the nonphotosensitive polyimide 13, and the overhangs 18 of the nonphotosensitive polyimide 13 are removed by performing wet etching again. And the tapering processing of the via holes 17 is performed, and heating and hardening is performed. |
